ArmPkg: Handle FFA_BUSY response for MM communication#1825
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Submit to edk2 in parallel?
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Well, this is actually one of many issues with this function. It's the most pressing so prioritizing it. Thinking is that we need a more complete fix we can probably do upstream first. |
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Tested on physical arm platform and booted to Windows 11 desktop. |
kuqin12
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yoeinhor
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Raymond-MS
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MM communicate is used at runtime, and the secure partition it is communicating with may provide services access through other means then the UEFI runtime services. As such, the MM communication library must not assume that the partition will be in the waiting state. Instead it must handle the case where the partition is busy and retry the communication to some limit. Signed-off-by: Chris Fernald <chfernal@microsoft.com>
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Description
MM communicate is used at runtime, and the secure partition it is communicating with may provide services access through other means then the UEFI runtime services. As such, the MM communication library must not assume that the partition will be in the waiting state. Instead, it must handle the case where the partition is busy and retry the communication to some limit.
Observed issue
This specifically resolves a bugcheck observed booting to Windows on multiple platforms where the variable services are access through the runtime services at the same time that the TPM PPI is invoking StMM to access the PPI variables. This causes a busy response in the runtime services, which are not currently handled. The inverse is already handled as the ACPI FFH opregion handling for FF-A already accounts for busy responses.
How This Was Tested
Integration Instructions
N/A